多项式微分系统的不变直线的不同斜率的最大个数

本文证明了公式β（ｎ）＝σ（ｎ－１）＋１其中α（ｎ－１）是ｎ－１次多项式微分系统的不为直线的最多条数，βｎ）是ｎ次多项式微分系统的不变直线的不同斜率的最大个数。这里假设所讨论的多项式系统只有限条不变直线。     

Slip zone and energetics of a large earthquake from the Taiwan Chelungpu-fault Drilling Project

Determining the seismic fracture energy during an earthquake and understanding the associated creation and development of a fault zone requires a combination of both seismological and geological field data. The actual thickness of the zone that slips during the rupture of a large earthquake is not known and is a key seismological parameter in understanding energy dissipation, rupture processes and seismic efficiency. The 1999 magnitude-7.7 earthquake in Chi-Chi, Taiwan, produced large slip (8 to 10 metres) at or near the surface, which is accessible to borehole drilling and provides a rare opportunity to sample a fault that had large slip in a recent earthquake. Here we present the retrieved cores from the Taiwan Chelungpu-fault Drilling Project and identify the main slip zone associated with the Chi-Chi earthquake. The surface fracture energy estimated from grain sizes in the gouge zone of the fault sample was directly compared to the seismic fracture energy determined from near-field seismic data. From the comparison, the contribution of gouge surface energy to the earthquake breakdown work is quantified to be 6 per cent.     

Targeting of cell-surface beta-amyloid precursor protein to lysosomes: alternative processing into amyloid-bearing fragments.

Progressive cerebral deposition of the amyloid beta-peptide is an early and invariant feature of Alzheimer's disease. The beta-peptide is released by proteolytic cleavages from the beta-amyloid precursor protein (beta APP), a membrane-spanning glycoprotein expressed in most mammalian cells. Normal secretion of beta APP involves a cleavage in the beta-peptide region, releasing the soluble extramembranous portion and retaining a 10K C-terminal fragment in the membrane. Because this secretory pathway precludes beta-amyloid formation, we searched for an alternative proteolytic processing pathway that can generate beta-peptide-bearing fragments from full-length beta APP. Incubation of living human endothelial cells with a beta APP antibody revealed reinternalization of mature beta APP from the cell surface and its targeting to endosomes/lysosomes. After cell-surface biotinylation, full-length biotinylated beta APP was recovered inside the cells. Purification of lysosomes directly demonstrated the presence of mature beta APP and an extensive array of beta-peptide-containing proteolytic products. Our results define a second processing pathway for beta APP and suggest that it may be responsible for generating amyloid-bearing fragments in Alzheimer's disease.     

大跨度钢筋混凝土空腹夹层板柱结构研究与应用

介绍一种新型的大跨度钢筋混凝土空间反系结构－钢筋混凝土空腹夹层板柱结构,它具有板系结构的力学优点,板系结构可跨越更大的跨度。它集承重、围护、装修、管道支架吊顶为一体,经济适用、造型美观、施工方便,是一种值得在大跨度钢筋混凝土屋盖和楼盖结构中推广使用的优良结构形式。     

金花茶组植物订正

本文订正了山茶属金花茶组的系统分类,合并了7个异名种和5个变种,另把2个变种提为新组合种。文章对金花茶组的特性和变异性作了较全面的探讨,然后提出合并和提升的依据。     

硬脂酰苯并三唑的合成及其反应活性

采用二环己基碳二亚胺缩合法由硬脂酸和苯并三唑合成了硬脂酰苯并三唑,产率85%,并利用FT-IR和1HNMR对产物进行了表征;硬脂酰苯并三唑在胰岛素的化学修饰中呈现较高的酰化反应活性及选择性,并进一步证实该酰化苯并三唑的合成是成功的.